• Jan Kara's avatar
    writeback: Write dirty times for WB_SYNC_ALL writeback · dc5ff2b1
    Jan Kara authored
    Currently we take care to handle I_DIRTY_TIME in vfs_fsync() and
    queue_io() so that inodes which have only dirty timestamps are properly
    written on fsync(2) and sync(2). However there are other call sites -
    most notably going through write_inode_now() - which expect inode to be
    clean after WB_SYNC_ALL writeback. This is not currently true as we do
    not clear I_DIRTY_TIME in __writeback_single_inode() even for
    WB_SYNC_ALL writeback in all the cases. This then resulted in the
    following oops because bdev_write_inode() did not clean the inode and
    writeback code later stumbled over a dirty inode with detached wb.
    
      general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
      Modules linked in:
      CPU: 3 PID: 32 Comm: kworker/u10:1 Not tainted 4.6.0-rc3+ #349
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
      Workqueue: writeback wb_workfn (flush-11:0)
      task: ffff88006ccf1840 ti: ffff88006cda8000 task.ti: ffff88006cda8000
      RIP: 0010:[<ffffffff818884d2>]  [<ffffffff818884d2>]
      locked_inode_to_wb_and_lock_list+0xa2/0x750
      RSP: 0018:ffff88006cdaf7d0  EFLAGS: 00010246
      RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88006ccf2050
      RDX: 0000000000000000 RSI: 000000114c8a8484 RDI: 0000000000000286
      RBP: ffff88006cdaf820 R08: ffff88006ccf1840 R09: 0000000000000000
      R10: 000229915090805f R11: 0000000000000001 R12: ffff88006a72f5e0
      R13: dffffc0000000000 R14: ffffed000d4e5eed R15: ffffffff8830cf40
      FS:  0000000000000000(0000) GS:ffff88006d500000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000000003301bf8 CR3: 000000006368f000 CR4: 00000000000006e0
      DR0: 0000000000001ec9 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
      Stack:
       ffff88006a72f680 ffff88006a72f768 ffff8800671230d8 03ff88006cdaf948
       ffff88006a72f668 ffff88006a72f5e0 ffff8800671230d8 ffff88006cdaf948
       ffff880065b90cc8 ffff880067123100 ffff88006cdaf970 ffffffff8188e12e
      Call Trace:
       [<     inline     >] inode_to_wb_and_lock_list fs/fs-writeback.c:309
       [<ffffffff8188e12e>] writeback_sb_inodes+0x4de/0x1250 fs/fs-writeback.c:1554
       [<ffffffff8188efa4>] __writeback_inodes_wb+0x104/0x1e0 fs/fs-writeback.c:1600
       [<ffffffff8188f9ae>] wb_writeback+0x7ce/0xc90 fs/fs-writeback.c:1709
       [<     inline     >] wb_do_writeback fs/fs-writeback.c:1844
       [<ffffffff81891079>] wb_workfn+0x2f9/0x1000 fs/fs-writeback.c:1884
       [<ffffffff813bcd1e>] process_one_work+0x78e/0x15c0 kernel/workqueue.c:2094
       [<ffffffff813bdc2b>] worker_thread+0xdb/0xfc0 kernel/workqueue.c:2228
       [<ffffffff813cdeef>] kthread+0x23f/0x2d0 drivers/block/aoe/aoecmd.c:1303
       [<ffffffff867bc5d2>] ret_from_fork+0x22/0x50 arch/x86/entry/entry_64.S:392
      Code: 05 94 4a a8 06 85 c0 0f 85 03 03 00 00 e8 07 15 d0 ff 41 80 3e
      00 0f 85 64 06 00 00 49 8b 9c 24 88 01 00 00 48 89 d8 48 c1 e8 03 <42>
      80 3c 28 00 0f 85 17 06 00 00 48 8b 03 48 83 c0 50 48 39 c3
      RIP  [<     inline     >] wb_get include/linux/backing-dev-defs.h:212
      RIP  [<ffffffff818884d2>] locked_inode_to_wb_and_lock_list+0xa2/0x750
      fs/fs-writeback.c:281
       RSP <ffff88006cdaf7d0>
      ---[ end trace 986a4d314dcb2694 ]---
    
    Fix the problem by making sure __writeback_single_inode() writes inode
    only with dirty times in WB_SYNC_ALL mode.
    Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
    Tested-by: default avatarLaurent Dufour <ldufour@linux.vnet.ibm.com>
    Signed-off-by: default avatarJan Kara <jack@suse.cz>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
    dc5ff2b1
fs-writeback.c 70.3 KB